Gravity Waves

Gravity waves are ripples in the curvature of space time that propagate as waves at the speed of light. They are generated in certain gravitational interactions that propagate outward from their source. Gravitational waves have been inferred from watching two pulsars spinning and noticing they are slowing down, due to losing energy from emitting gravitational waves. 

Gravity waves were discovered by Russell Alan Hulse and Joseph Hooton Taylor Jr. Gravitational waves are generated by two merging black holes. Gravitational waves are important in telling us about the early universe and it gives us a snapshot of the universe about 380,000 years after the start of the universe. 

Gravitational waves were detected 100 years after Einstein's prediction. They were also predicted to exist in 1916."The waves tore through the cosmos at the speed of light and arrived at Earth just in time for the start-up of the Advanced Laser Interferometer Gravitational-Wave Observatory, LIGO, which measured the minute stretching and squeezing of space."- sciencenews.org

When an object accelerates in space, it creates ripples in space and that creates gravity waves. "Long ago, deep in space, two massive black holes—the ultrastrong gravitational fields left behind by gigantic stars that collapsed to infinitesimal points—slowly drew together. The stellar ghosts spiraled ever closer, until, about 1.3 billion years ago, they whirled about each other at half the speed of light and finally merged. The collision sent a shudder through the universe: ripples in the fabric of space and time.."-sciencemag.org

Gravitational waves happen because it changes the way we understand the nature of space, time and gravity. "The first waves detected, spotted in data collected on September 14, 2015 were the result of two black holes 36 and 29 times the mass of our sun merging. The second set of gravitational waves were sent travelling through spacetime when two black holes eight and 14 times the mass of our sun collided."-wired.co.uk